There is one other use for the disposables.
At MY wedding, I had a photographer friend work. Before the wedding he met some guest, they fell in love, and spent most of our reception off making out somewhere. And he was so distracted he did not set the shutter speed right on the camera, so the formal portraits had that shutter-curtain-drag effect from not being synched.
We had just attended a wedding with the disposables and thought it was a "cute" idea. So we did it and thank God...our ONLY wedding pictures were from those!
The exception, not the rule, of course. But it biases my view of having the disposables there too.